EFFICIENCY OF THE COW HERD: BULL SELECTION AND GENETICS

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1 EFFICIENCY OF THE COW HERD: BULL SELECTION AND GENETICS Oregon State University/Beef Industry Tour Corvallis, Oregon Thursday, October 25, 2018 Overview Introduction/importance of sire selection Selection emphasis Evolution of beef cattle evaluation Use of genetic tools (EPDs, indexes, etc.) DNA information J. Benton Glaze, Jr., Ph.D. Extension Beef Cattle Specialist Introduction The major objective (aim) of all beef cattle producers should be to increase genetically the producing ability of cattle in their herds Importance of Sire Selection Most genetic progress is made through sire selection Decisions have long-term impact In herds where replacements are saved, 87.5% of the genetic makeup of each calf results from the last three sires used 1

2 Introduction Tips for increased beef cow profits (BEEF, 2013) Focus on the target Donnell Brown Select the cow that best fits your environment Select the bull that best complements the cow to produce a calf that fits the market Select breeding and mating systems that fits your management Use of Genetic Tools in Selection Information type Used in last 5 years (%) Use in the future (%) Actual measurements Ratios Expected progeny differences (EPDs) Genomically enhanced EPDs Productivity of relatives Comments by seller DNA marker results None of above (Weaber et al., 2014) Traits of Interest Bull Selection (BEEF, 2014) Traits of Interest Bull Selection (BEEF, 2014) Actual birth weight* 72.9% Scrotal EPD* 34.9% Birth weight EPD 68.6% Carcass EPDs* 33.0% Calving ease direct EPD* 58.5% Actual disposition score* 30.3% Actual weaning weight 55.3% Disposition EPD* 30.2% Weaning weight EPD 52.9% Adj. yearling weight* 28.7% Milking ability EPD 51.2% Feed efficiency EPD* 28.3% Yearling weight EPD* 45.7% Feedlot performance EPDs 17.9% Calving ease maternal EPD* 43.3% Stayability EPD* 14.7% Adj. yearling scrotal measure 41.5% Economic index EPD* 13.1% Actual yearling weight 40.2% Heifer pregnancy EPD* 10.8% Adj. weaning weight* 39.4% Gestation length EPD* 5.1% (* = traits with percentages that increased from 2010) Trait % Trait % Actual birth weight 72.9 Birth weight EPD 68.6 Actual weaning weight 55.3 Weaning weight EPD 52.9 Actual yearling weight 40.2 Yearling weight EPD 45.7 Adj. scrotal measures 41.5 Scrotal EPD 34.9 Actual disposition score 30.3 Disposition EPD 30.2 Producers requiring actual data versus EPDs Producers may not always use best source of information for selection 2

3 Components of Performance Performance = Genetics + Environment Evolution of Beef Cattle Evaluation Visual Appraisal Measurement on a given animal Sum of the genetic factors that influence the measurement Sum of the management and climatic factors that influence the measurement Actual Performance Measures Adjusted Measures & Within Herd Ratios Expected Progeny Differences Bioeconomic Values Genomic-Enhanced EPD & Indexes BW WW YW d WT RATIO 205-d WT RATIO BW WW YW MILK MARB EPD EPD EPD EPD EPD (.85) (.83) (.78) (.40) (.34) $W $F $GRID $BEEF API TI Expected Progeny Difference (EPD) EPD genetic merit of an animal, as a potential parent, in comparison with other animals in the same breed Expressed in trait units (lbs, in, cm, in 2, etc.) Supplied by breed associations Published in sire summaries, catalogs, etc. Expected Progeny Difference (EPD) EPD estimate of the genetic merit of future progeny of an animal based on its pedigree, its own performance, and the performance of its progeny EPD best method for predicting an animal s genetic level or genetic worth 3

4 EPD: Accuracy (ACC) EPD are estimates accuracy indicates how closely the estimates are to the true values Provides measure of reliability or certainty Ranges in value from zero (poor estimate) to one (good estimate) Increases with additional data (information) Does not indicate progeny variability EPD: Accuracy Categories Accuracy Meaning Risk Level < to t0.80 >.80 Very likely to change as information is added Some changes likely; records on few progeny Small changes possible; records on numerous progeny Not likely to change much as information is added High Moderate Low Very Low EPD: Possible Change (PC) Values are standard deviations PC = standard error of prediction EPD: Accuracy and Possible Change Possible Change Table MILK MWW STAY ACC CE BW WW YW MCE CW YG MARB BF REA WB PC is associated with accuracy (ACC) Higher ACC = less chance of change Smaller PC values Lower ACC = greater chance of change Larger PC values

5 Possible Change Table ACC CE BW WW Sire CE ACC Possible Change True EPD Range A to 17.0 B to 10.8 Sire BW ACC Possible Change True EPD Range A to 4.40 B to 2.60 Sire WW ACC Possible Change True EPD Range A to 76.4 B to 69.9 Genomic Enhanced EPDs Provide ability to better characterize cattle in a breed Provide improved accuracies (ACC) on non-parent animals Provide better overall breeding values Better estimates of an animal s genetic worth Genomics Influence on Accuracy Genomic Enhanced EPDs Genomic test results are incorporated into EPD calculations Accuracy impacts are dependent on the proportion of the additive genetic variance explained by genomic results Most traits ~15 50% Depending on the trait, genomic results are similar to 8-20 progeny records 5

6 Example: EPD Use and Interpretation SIRE A B Expected Progeny Difference (EPD)* CE (ACC) BW (ACC) WW (ACC) YW (ACC) MILK (ACC) 4.7 (0.38) 3.9 (0.75) 46 (0.72) 92.5 (0.72) 6.7 (0.59) CE (ACC) BW (ACC) WW (ACC) YW (ACC) MILK (ACC) 11.2 (0.46) -1.8 (0.75) 20.4 (0.72) 62.9 (0.71) 27.7 (0.50) Difference *Abbreviations: CE = Calving ease BW = Birth weight WW = Weaning weight YW = Yearling weight MILK = Milk ACC = Accuracy Example: EPD Use and Interpretation SIRE A B Expected Progeny Difference (EPD) CE (ACC) BW (ACC) WW (ACC) YW (ACC) MILK (ACC) -1.1 (0.78) 3.2 (0.91) 42.1 (0.85) 78.2 (0.81) -1.1 (0.52) CE (ACC) BW (ACC) WW (ACC) YW (ACC) MILK (ACC) 16.7 (0.29) -2.9 (0.65) 17.3 (0.41) 28.4 (0.39) 2.8 (0.27) Difference Sire A s progeny are expected to be, on average: 6.1 pounds heavier at birth 24.8 pounds heavier at weaning 49.8 pounds heavier at a year of age Example: EPD Use and Interpretation SIRE A B Expected Progeny Difference (EPD) CE (ACC) BW (ACC) WW (ACC) YW (ACC) MILK (ACC) -1.1 (0.78) 3.2 (0.91) 42.1 (0.85) 78.2 (0.81) -1.1 (0.52) CE (ACC) BW (ACC) WW (ACC) YW (ACC) MILK (ACC) 16.7 (0.29) -2.9 (0.65) 17.3 (0.41) 28.4 (0.39) 2.8 (0.27) Difference On average, when mated to heifers, 17.8% less of Sire B s calves should require assistance compared to Sire A s calves. Sire B s daughters are expected to wean calves that are 3.9 pounds heavier than calves from daughters of Sire A. EPD: Indexes Index a combination and weighting of multiple traits and their relative economic impact into one value that can be used to rank animals Challenging to develop Simplistic too use Provides directional change in multiple traits Index = yearling weight (3.2 x birth weight) 6

7 EPD: Indexes Economic index collection of EPDs weighted by their economic value so that traits with greater impacts on production goals have larger economic weights I = EPD 1 x a 1 + EPD 2 x a EPD n x a n Where: I = index value EPD n = EPD for trait n a n = economic weight for trait n EPD: Indexes Index EPD Examples Economic index (Index EPD) referred to as $value indexes Combine EPD for traits affecting an overall measure of production, value of that production, and the cost to obtain it Mathematical weightings are applied to input traits and the value and costs of production are assigned Usually reported in net dollar return Angus Cow Energy Value Weaned Calf Value Feedlot Value Grid Value (QG, YG) Beef Value Charolais Terminal Sire Profitability Index Limousin Mainstream Terminal Index Gelbvieh Feedlot Merit Index Carcass Value Index Hereford Baldy Maternal Index Calving EZ Index Brahman Influence Index CHB Index Simmental All-Purpose Index Terminal Index 7

8 Angus - $Value Indexes Weaned calf value ($W) expected difference in future progeny for preweaning merit Expressed in dollars per head ( = favorable) Traits: BWT, WWT, maternal milk, mature cow size Cow energy value ($EN) expected difference in cow energy needs in daughters of sires Expressed in dollars savings per cow per year ( = favorable) Traits: lactation energy requirements, energy cost, mature cow size Example: EPD Use and Interpretation SIRE A Expected Progeny Difference (EPD)* $W $F $G $B $EN $W $F $G $B $EN B Difference *Abbreviations: $W = Weaned calf value $F = Feedlot value $G = Grid value $B = Beef value $EN =Cow energy value Example: EPD Use and Interpretation SIRE A Expected Progeny Difference (EPD) $W $F $G $B $EN $W $F $G $B $EN B Difference Sire A s progeny are expected to have, on average: $18.13 advantage in pre-weaning value Sire B s daughters are expected to have, on average: $42.50 per cow, per year energy cost savings EPD: Indexes Index EPDs allow for simultaneous selection for more than one trait Index EPDs are to be used within breed Index EPDs lack published accuracies Caution with young sires index can change Index EPDs should be used within specific production goals Terminal versus maternal 8

9 Index EPD Examples DNA Testing Maternal Cow Energy Value (AN) Weaned Calf Value (AN) All Purpose Index (SM) Baldy Maternal Index (HP) BR Influence Index (HP) Calving EZ Index (HP) Herdbuilder (RA) $Cow Index (GV) Terminal Beef Value Index (AN) Feedlot Value Index (AN) Grid Value Index (AN) Terminal Index (SM) CHB$ Index (HP) Mainstream Terminal (LM) Terminal Sire Index (CH) Collect Sample Extract DNA Genotype Analyze Interpret/Consult Genetic markers DNA Test Results SNPs most common type of genetic variation in animals SNPs represent a difference in a single nucleotide SNPs occur normally in an animal s DNA Occur every 300 nucleotides = ~ 10 million SNPs 9

10 DNA Test Results DNA Test Results Animal Score CED HP RFI Score CED HP RFI Animal Genetic Effects CED HP RFI Score CED HP RFI A B A B Difference CED: A is expected to have 13.2% more unassisted calves HP: A is expected to have daughters with 7.2% higher probability of conceiving RFI: B progeny is expected to require 1.1 lb/d less feed for same ADG How do you define efficiency? Pounds of calf weaned per cow - (18%) Percent of cow weight weaned - (14%) Pounds of calf weaned per cow exposed - (21%) Pounds of calf weaned per unit of feed - (14%) Pounds of calf weaned per acre - (7%) Pounds of beef produced per cow - (21%) None of above - (4%) Importance of Reproduction In the past 25 years or so, the beef industry has made great strides in improving performance related traits Genetic improvement programs for reproductive traits have been slower to develop Reproductive performance is the most important economic trait in a beef cow herd 10

11 Importance of Reproduction In relative economic terms, reproduction has been reported to be: 5 times more important than production traits 4 times more important than end-product traits Importance of Reproduction Historically, producers have experienced difficulty in selecting for reproduction Reproduction is a complex trait with many inputs Limited agreement on how reproduction is defined or expressed Limited genetic control Reproductive Trait EPDs Scrotal Circumference (SC) EPD Expressed in centimeters and represents sire s ability to transmit scrotal growth Larger numbers = larger scrotal circumferences Reproductive Trait EPDs Heifer Pregnancy (HP) EPD Expressed as a difference in % of a sire s daughters conceiving to calve at two years of age Greater numbers = more pregnant heifers Larger numbers = improved semen traits, decreased age of puberty 11

12 Reproductive Trait EPDs Stayability (STAY) EPD Expressed as a difference in % of a sire s daughters remaining in herd until at least six years of age Greater numbers = more cows staying in herd for longer periods Efficiency EPDs Dry Matter Intake (DMI) EPD Expressed in pounds per day; predicts the difference in transmitting ability for feed intake during postweaning period Lower numbers = less DM consumed per day Efficiency EPDs Residual ADG (RADG) EPD Expressed in pounds per day; predicts a sire s transmitting ability for postweaning gain given a constant amount of feed consumed Greater numbers = more ADG Genetic Antagonisms / Correlations Genetic antagonism situation in which favorable genetic change in one trait is accompanied by unfavorable genetic change in another trait Causes: plieotropy, genes closely linked in the genome Identified (measured) with genetic correlations 12

13 Genetic Correlations Can be positive or negative (+) When one trait changes, other trait changes in same direction (-) When one trait changes, other trait changes in opposite direction Can be favorable or unfavorable Provides a desirable outcome Provides an unfavorable outcome Genetic Correlations - Examples Examples of genetic correlations: Calving ease & birth weight (-, unfavorable) Growth traits & SC (+, favorable) Milk & maintenance energy (+, unfavorable) WW & fat thickness (-, favorable) Genetic Correlations - Examples Genetic Correlations - Examples Selection for postweaning gain Increased age and weight at puberty, increased mature weight Improved fertility Reduced maternal gestation length and calving difficulty Increased birth weight and reduced pre-weaning gain Selection for increased RP or CW Increased age and weight at puberty, increased mature weight Improved fertility Increased gestation length and BW Reduced calving difficulty and maternal pre-weaning gain Selection for reduced fat thickness Increased age and weight at puberty, increased mature weight Reduced fertility and pre-weaning gain Reduced maternal gestation length, BW and calving difficulty 13

14 Selection Strategies Define goals and objectives, identify strengths and weaknesses Identify, and select for, traits of economic importance Utilize EPDs as a selection tool Utilize visual appraisal to ensure sire can contribute his genetic characteristics Track herd performance and match to environment and markets Take steps to positively impact end product acceptability THANK YOU! Benton Glaze, Ph.D. University of Idaho P. O. Box 1827 Twin Falls, ID (208) Questions? 14